[ofa-general] Re: [PATCH] opensm: Implement weighted routing

[Dale Purdy]

On Thu, Feb 26, 2009 at 10:21:43AM +0530, Keshetti Mahesh wrote:
> Hello Dale Purdy,
> 
> I have a requirement where I have to set the some hop's weight
> factor to zero. Is this supported by your patch ?
> I have implemented something similar to it before but it lead to
> loops in the routing table. Does your patch take care of those things ?
> 
> -Mahesh

No, the accepted values for the hop weight are 1 - 0xff.  I suppose
one could allow a value of zero though.  Or one could raise the weight
factor for the other ports on the switch to a large value so that the
one you are trying to force traffic through is highly favored in
comparison.  Whenever you are manipulating the hop weight factors, you
better know what you are doing since it alters the behavior of the
routing engines and could then induce credit loops.  In our case we
are using this to separate MPI traffic from I/O traffic and at the
same time eliminate credit loops.

-- 
Dale